Optical brightening agents



.K. g a.

United States Patent 2,762,802 OPTICAL BRIGHTENTNG AGENTS Heinrich Hiiusermann, Basel, Switzerland, assignor to J. R. Geigy A.-G., Basel, Switzerland, a Swiss firm No Drawing. Application March 28, 1955, Serial No. 497,423 Claims priority, application Switzerland March 31, 1954 6 Claims. (Cl. 260--249.6)

The present invention concerns optical brightening agents, that is, compounds which is slight amounts on more or less white substrata bring about an optical brightening in daylight due to their violet-blue, blue to greenishblue fluorescence. In particular it is concerned with derivatives of 4.4-diaminostilbene 2 monosulphonic acids which possess new and valuable properties, with processes for the production of such compounds and their use for the brightening of more or less white substrata, as Well as with the material brightened with the help of these compounds. It is known that 4.4-diaminostilbene-2.2'-disulphonic acid is a valuable starting material for the production of the optical brightening agents used in technics. Products of this type are obtained for example by the introduction of aroyl, phenylcarbamyl or 1.3.5-triazinyl radicals into the amino groups of the main substance, within certain margins, the water solubility, the substantivity, the intensity of fluorescence and the colour of the fluorescence light can be influenced by the substitution of these radicals. Given favourable intensity of fluorescence and blue to greenish-blue fluorescence colour, often the water solubility and the substantivity, which is often influenced by the water solubility, decide the usefulness of such compounds as additives to anion active wetting and cleaning agents in washing and rinsing liquors for textile washing. This range of application is of particular industrial interest because cleansing agents containing optical brightening agents are used in great amounts.

It has now been found that the water solubility, substantivity, intensity of fluorescence and colour of fluorescence can be influenced in optically active derivatives of 4.4-diaminostilbene not only by substitution of the aroyl or the tn'azinyl radicals but also often with advantage it can be favourably influenced by substitution of the stilbene radical. Thus, for example, 4.4-bis-triazinyl-aminostilbene compounds which, for optical reasons, contain the substituted amino groups in the triazinyl radical which increase the Water solubility can be more suitable for use in Washing liquors if they are derived from a 4.4-diaminostilbene-Z-monosulphonic acid than analogous derivatives of 4.4'-diaminostilbene-2.2-disulphonic acid. In this case, the o-position to the ethylene linkage in the unsulphonated benzene ring of the stilbene radical can be unsubstituted or it can be occupied by non-ionogenic substituents, e. g. by halogen, alkyl, cyano, alkylsulphonyl, arylsulphonyl, sulphonic acid amide (including sulphonic acid amide organically substituted at the nitrogen atom), or acyl substituents. In this position, the positivising substituents have a particularly marked eifect on the colour of the fluorescence light; this is relatively slighter with methyl, isopropyl and tert. butyl groups, but very marked with alkoxy groups such as, for example, methoxy, ethoxy, propoxy, butoxy, methoxyethoxy, ethoxyethoxy or benzyloxy groups as well as with the hydroxyethyl or the hydroxypropyl group. These alkoxy groups in the o-position to the ethylene linkage of the stilbene radical cause the greatest shifting of the colour of the fluorescence light from violet or blue towards green. This is a particularly valuable property in 4.4'-bis-triazinylaminostilbene compounds because analogues derived from 4.4- diaminostilbene-2.2-disulphonic acid often have an undesirable reddish-blue fluorescence. If derivatives of 4.4- diaminostilbene-2.2-disulphonic acid have a too reddish fluorescence, the colour of the fluorescence light in the corresponding derivatives of a 4.4 diamino 2 alkylstilbene-2-sulphonic acid is shifted towards blue and in those of a 4.4-diamino-2-alkoxystilbene-2-sulphonic acid it is shifted towards greenish-blue; The compounds derived from 2-a1kylor 2-alkoxy-4.4'-diaminostilbene-2'- sulphonic acids and in particular the bistriazinyl derivatives thereof, are the most valuable brightening agents according to this invention. Apart from the substitution of the stilbene radical in the o-position to the ethylene linkage mentioned above, if desired non-ionogenic substituents of the type defined above can also occupy other positions in the two benzene rings of the stilbene radical.

New optical brightening agents according to this invention are obtained if compounds of the general Formula I Y Y2 (I) wherein the one X represents hydrogen, a carbacyl radical or a 1.3.5-triazinyl radical and the other X represents hydrogen, the one Y represents the free sulphonic acid group of one neutralised by bases, and the other Y represents hydrogen or a non-ionogenic substituent, preferably a low molecular alkyl or alkoxy group, and wherein the benzene rings of the stilbene radical can possibly contain further non-ionogenic substituents, are reacted with compounds introducing 1.3.5-triazinyl radicals or carbacyl radicals until the primary amino groups have disappeared. In this reaction the components should be so chosen that in the end product at least one X represents either an aminosubstituted 1.3.5-triazinyl radical, an aryl carbamyl radical or an aroyl radical, of which the latter is substituted preferably in at least an 0- or p-position to the carbonyl group by substituents having a positivising action, e. g. it contains a p-methyl, p-alkoxy, p-hydroxyalkoxy or a p-acetamino and/ or an o-alkoxy or hydroxyalkoxy' group. Any mobile substituents in the 1.3.5- triazinyl radicals can also be replaced entirely or in part later by methods known per se by other substituents, in particular by positivising groups, preferably by amino groups, which, if desired, can be organically substituted. They may also be replaced, however, by, for example, the hydroxyl, an aryloxy group, alkyl or aryl-mercapto group.

Radicals of organic carboxylic acids including organic derivatives of carbonic acid are termed carbacyl radicals. Preferably the acid halides and possibly also the acid anhydrides are compounds which introduce the carbacyl radicals. For the purpose of this invention, radicals of lower fatty acids, radicals of carbonic acid half esters with lower alcohols, radicals of carbamic acids, preferably, however, aroyl radicals of the benzene series, possibly also of the naphthalene series, can be used as carbacyl radicals. Suitable aroyl radicals are, for example, the benzoyl, p-methylbenzoyl, p-methoxybenzoyl, p-ethoxybenzoyl, o-methoxybenzoyl, o ethoxybenzoyl, 0.;3-hydroxyethoxybenzoyl, p-methyl o methoxybenzoyl, pmethyl-o-ethoxybenzoyl, p-methyl 0.3 hydroxyethoxybenzoyl, 2.4-dimethoxybenzoyl, 2-methoxy-3-naphthoyl or the 2-ethoxy-3-naphthoyl radical. Under suitable conditions, also isocyanates and bisulphate addition compounds thereof can be used as compounds introducing carbamyl radicals.

Cyanuric halides, in particular cyanuric chloride, can

be used as compounds which introduce the 1.3.5-triazinyl radical. Their halogen atoms can be reacted by methods known per se, in the cold in the first step, at medium temperatures in the second step and at higher temperatures in the third step, the reaction being performed in the presence of acid binding agents. To introduce the 1.3.5-tri'azinyl radical into compounds of the general Formula I, it is advantageous to use these cyanuric halides in aqueous suspension in the first step. They may also possibly be used in the second step insofar as the amide radical introduced in the first step has the properties which bring about water solubility. All or some of the halogen atoms remaining at the cyanuric ring are later replaced, preferably by amide radicals. If desired however, some of them can also be replaced by other positivising groups, for example, by the hydroxyl, a phenoxy group, an alkylmercapto or phenylmercapto group.

Suitable amide radicals are derived from ammonia and, preferably, from primary and secondary organic amines. Alkyl, hydroxyalkyl, aralkyl, cycloalkyl, aryl groups (preferably phenyl and substituted phenyl groups) and also heterocyclic radicals are examples of organic radicals thereof. In heterocyclic amide radicals the nitrogen atom bound to the triazinyl radical can be a member of the hetero ring, such as for example in the piperidine and in the morpholine radical, or it can belong to the amino group of a heterocyclic amino compound, such as for example in Z-aminopyridine, in the Z-aminopyrimidine or in the Z-aminothiazole radical.

Compounds of the general Formula I which are usable according to the present invention are obtained for example according to the United States Patent No. 2,657,228, by condensation of 4-nitro-1-methylbenzene- 2-sulphonic acid aryl esters at higher temperatures in the presence of strong organic nitrogen bases with 4-nitro or 4-acylamino-benzaldehydes to form the corresponding stilbene monosulphonic acid aryl esters which are saponified by known methods to form the free sulphonic acids or the salts thereof. The non-ionogenic substituents usual in aromatic rings can also be contained in the 4-nitro-1-methylbenzene-Z-sulphonic acid aryl ester component, for example in the 6-position, and in the benzaldehyde component, in particular in the 4-acylaminobenzaldehyde component, in the 2-, 3-, 5- or 6- position. Examples of such substituents are halogen or alkyl, alkoxy, cyano, alkyl or aryl sulphonyl sulphonic acid amide groups and sulphonic acid amide groups organically substituted at the nitrogen atom.

If 4-acylamino benzaldehydes are used for the stilbene condensation, then after saponification, 4-nitro-4'-ar'ninostilbene-Z-sulphonic acids are obtained which are suitable for the formation of the brightening agents according to this invention which are unsymmetrical with regard to the substitution of the amino groups. For example, they can be reacted or acylated with cyanuric chloride and two molecules of ammonia or primary or secondary organic amines in the presence of acid binding agents, for example with an aroyl halide which may possibly be suitably substituted or with an arylisocyanate and then the nitro group is reduced to the amino group.

HOCHlOHSN .4 If the nitro groups are reduced to the amino groups first, then 4.4'-diaminostilbene-monosulphonic acids are obtained which are suitable for the formation of symmetrical amine derivatives.

In the form of their alkali salts, in particular, the lithium, potassium, sodium or ammonium salts, the new brightening agents are more or less strongly yellowish to yellow coloured powders which in water more or less easily according to the composition form colourless to weakly yellowish solutions. The aqueous solutions thereof have a strong fluorescence in ultra violet light. Finely distributed in or on more or less white substrata such as cellulose fibres, soaps, synthetic washing agents, polyamide fibres in a content of 0.001 to 0.1% according to the composition, they cause a strong brightening effect in daylight due to the blue fluorescence,

The following examples illustrate the production of some of the compounds according to the present invention and their use for the brightening of more or less white substrata. Where not otherwise stated, parts are given as parts by weight and the temperatures are in degrees centigrade. The relationship of parts by weight to parts by volume is as that of kilogrammes to litres.

Example 1 0 02115 SOQH 33.4 parts of 4.4 diamino-2-ethoxystilbene 2 sulphonic acid are suspended in 400 parts of pyridine and at 2030, 50 parts of p-methoxybenzoyl chloride are added all at once. The temperature rises spontaneously to about 50 and a clear brownish-yellow solution is formed which is stirred at 60-70 until no more free amine can be traced by the diazotisation test. This generally occurs after only a few minutes. The reaction mixture is then poured into 1500 parts of a 3% sodium chloride solution, caustic soda lye is added while stirring until phenolphthalein paper turns a strong red colour and the pyridine is distilled off with steam. After cooling, the sodium salt, of 4.4-di-(p-methoxybenzoylamino)- 2'-ethoxystilbene-2-sulphonic acid separates as a grey crumbly mass which is washed with 2 /2% sodium chloride solution and then dried. A yellowish-grey powder is so obtained which dissolves in hot water. In diluted alcohol, the new stilbene derivative dissolves with a blue fluorescence. If cellulose materials which are colourless or have a weakly yellowish appearance are treated with a diluted aqueous solution of this product, then the material treated has a much lighter appearance in daylight than before the treatment. The brightening attained is distinguished chiefly by its blue-green shade.

Somewhat weaker products are obtained if in this example instead of p-methoxybenzoyl chloride, the same amounts of p-methylbenzoyl chloride or benzoyl chloride are reacted with 4.4-diamino-2-ethoxystilbene-Z-sulphonic acid.

The 4.4'-diamino-2'-ethoxystilbene-Z-sulphonic acid used in this example can be easily produced, for example in the following manner: 4-acetylamino-2-ethoxybenzaldehyde (Melting Point 136) is condensed at 145 in the presence of piperidine with 4-nitrotoluene-2-sulphonic acid phenyl ester; the 4-nitro-4-acetylamino-2-ethoxystilbene-Z-sulphonic acid phenyl ester (M. P. -181") obtained is saponified and the nitrosulphonic acid is reduced to aminosulphonic acid.

6 35 parts of 4.4'-diamino-2-(fi-hydroethoxy)-stilbene 2- parts of sodiumcarbonate in 106 parts of water. The sulphonic acid, produced by condensation of 4-acetylsodium salt of 4.4'bis-[4-(m-sulphophenylamino.) 6- amino-2-(B-hydroxyethoxy)-benzaldehyde with -4-nitrochloro-l.3.5-triazinyl-(2)-aminol-2'-methoxystilbene" 2- toluene-2-sulphonic acid phenyl ester to form the 4-nit12osulphonic acid obtained is then heated in aqueous solu- 4'-acetylamino-2-(p-hydroxyethoxy)-stilbene=2-sulphonic 5 tion with 9 parts of --N-methyl-m0noethanolamine and 10.6 acid phenyl ester, M. P. 196, reduction ofthe nitro to parts of sodium carbonate for 2 hours at-9.01 00".. The

the amino group and saponification, are dissolved with resulting trisodium salt of 4.4'-bis-[4(mesulphophenylsodium carbonate to produce a neutral'reaction in 700 amino)-6-(fl-hydroxyethyl-methylamino) l:3.5 -triazinylparts of water. It is then reacted in the usual way first (2)-amino] -2-methoxystilbene-2-su1phonic acid is prewith 37 parts of cyanur ic-chloride and then with "18.6 10 "cipitated-by s'alting out W-ith"25% sodium chloride. After "parts-of aniline and at the same time, an aqueous solufiltering under suction, washing'with20% sodium chlotion of 21.2 parts "of sodiumcarbonate is added dropridesolution anddrying, the-new stilbene-derivative'is a wise. The yellowish suspension obtained is-then' heated 'pale yellowish powder which is easily soluble in water. for 4 hours at 90 100, N methyl monoethan'olamine "The aqueouss'olution fluoresces green-blue in ultraviolet being added to keepthe=reaction phenol-phthalein alkaline. light.

At the end of this time, -10-parts percent by volume of If colourless or weakly=yellowish cellulosematerials are sodium chloride -are added. After-cooling, the -precipitreated with a dilutedaqueous solution of this product, tated sodium salt of -4.4'=bis-E4ephenylamino 6-(fl hythen theyhave a strong blue fiuorescencein ultra violet 'droxyethyl'-m'ethyl'amino) 1I3.'5triazinyl-(2) amino'] 2- light and in daylight they-have 'amuch more white ap- (fl-hydroxye'thoxy)-stilbene 2=sulphonicacid is filtered-off g pearance. The analogous derivative of 4.4-diaminostilunder suction, washed with "5% =sodium-chloride solution *bene 2.2f-disulphonic acid produces a much more violetty "and dried-in the vacuum at '80'-90. In this manner .a brightening effect. grey yellow powder is I obtained which dissolves in hot -Azprodu'ct which is alsostrongl-y active and has similar water. On colourless to weakly yel lowish cellulose fibres, properties is obtained if in this example the '9 'partsof this-product produces a blue-greenish brightening'ifect. N methyl monoethanolaniine are replaced by 7.3 parts of If in this example, the N-methyl-monoethanolamine is -m'onoethanolamine.

Example 5 HOCaHaN'H NHC2H4OH N -NHQcH=oH: NH- /N N 5 N% ZCQHUNH OCH: 03H NHC2H5 replace'cl' by morpholine, then a product with a similar l1'65parts of 4:4adiamino-Z'smethoxystilberieQ-sulphonic actionhut-which is somewhat more di'fiicultly soluble -is acid ?are dissolved in '500:parts of water with .2 parts of obtained. sodium :hydroxide and reacted .at .0" *with an aqueous- Example 3 omo-O-o ONHQC n=on34vno 0G0 CH5 OH 7 30.4 parts of 4.4-diamino-2' methylstilbene-2-su1phonic acetone suspension of 18.45 parts of cyanuric chloride. acid, produced by condensation aof 4-acetylairiino'-2=me th-. During the reaction 'the acid liberatedis neutralised by yl benzaldehyde with 4-nitrotoluene-2-sulphonic acidphenthe addi-iton of, in-all, 5.3 parts'dfrsodium carbonate. As yl ester to form 4-nitro-4'-acetylamino'-methylstilbenesoon as no freeamino groups can be traced, 6.1 parts of 2-sulphonic acid phenyl ester (MIP. 209 uncorrected), monoethanolarnine are added, the whole isheated"to'"30- reduction of the nitro to the amino group-and saponifica- 40 and 53 parts of a 10% sodium carbonate solution are tion, are reacted with parts of p-methoxy-benzolychlo- 50 poured in at this temperature over a period of 2-4 hours. ride as-described'in'Bxample-1. The-sodiumsaltof 4;4'- 'flhezyellowpulpy mixture ?is then .heatedto. 90 and is di (p=methoxybenzoylamino)-2 methylstilbene -'2 ---'sulheld-sat 9.0-.100" forSfhours, =the'reaction being kept phep'honic 'acid'isa yellow powder which dissolves inwater wnolphthalein.:alkaline with'ethylamine. TThesodiurn salt --'and which is suitable for the brightening of cellulose -Jof *4.=4'-;bis'-;['4eethylamino 6-(fi-hydroxyethylamino)-1.2.3- fibres. 55 itriazinyl-(2).-aminol:2emethoxystilbene-Z-sulphonic acid A so'mewha't less active product *is obtainedif in ithis sso;obtained:is completely precipitated with sodium'chloexample thezp-methoxybenzoylchloride isreplaced bythe c'ridcpit.is;isolated:and:dried. fThe;product forms a yellow same a'mountof p-methylbenz'oyl chloride or 'byl3i4-fdi- :powder:the:aqeous-alcholic solution ,of which fluoresces methylbenzoyl chloride. Iblue. product also is excellently suitable for the Example 4 Q .0... N NH mangle 3 O...

Ho-oHPoHPN 00H. 7 so=H III-0111011 013 CH1 7 GH:

16.0 parts of 4.4'-diamino-'2=meth'oxystilbene-2-sul- "brightening of cellulose fibres due to its blue fiu-oroescence phonic acid, produced by reduction and saponification of I d d ub tanti jt 9 i q' P FP 9 fPro'ducts'wi'th similar properties are. obtained if in the p'henyl- 'ester '(M. P. 200),are-reacted consecutively'an b 1 h fin l d f d "th'e usual-manner with 18.5 parts of cyanuricchlo'ride and We examp a 9 ensatlonlsfper (mm with 1 11925;paixt f.th ,sodjum sltief t flig dd w .-'N-methylethanolam1ne, fdiethanolamine, :monoethanoltralising the solution by the dropwise addition of 10.6 amine or morpholine instead of with ethylamine.

62.2 parts of the sodium salt of 4.4-[4.6-dichloro-1.3.5- 10 of water and reacted, at a pH value of 5.5-6.5, at with triazinyl-(2)amino] -2'-methylstilbene-2 sulphonic acid 36.9 parts or cyanuric chloride and 10.6parts ofsodiumcarare finely distributed by stirring in 2500 parts of water bonate. 85 parts of diethanolamine are added to the thick and heated to 3040. After adding 12.2 parts of monoyellowish suspension so obtained and the whole is stirred ethanolamine, the whole is stirred for another 5 hours at at 95100 for 4 hours under reflux. By salting out with 3040 during which time the pH value is adjusted to 7.5 25% sodium chloride the sodium salt of 4.4-bis-[4.6dito 8.2 by the slow addition of a solution of 21.2 parts of (di-[fi-hydroxyethyl]-amino)-l.3.5-triaZinyl-(2) amino]- sodium carbonate in 150 parts of Water. 30 parts of N- 2-methylstilbene-Z-sulphonic acid is precipitated as a yelmethyl-monoethanolamine are then added and the whole low body. After drying, the product is a water soluble is stirred at 90-100 for 6 hours. On the addition of 15 pale yellowish powder the aqueous solutions of which can parts by volume per cent of sodium chloride, the 4.4'-bisbe used for the brightening of cellulose fibres. [4-(B-hydroxy-ethylamino)-6 (,8 hydroxyethyl methyl- Similar products are obtained if in this example, the 30.4 amino)-1.3.5triazinyl-(2)amino] -2-methyl stilbene-2 parts of 4.4-diamino-2-methylstilbene-2-sulphonic acid sulphonic acid obtained precipitates from the clear yellow are replaced by 32.45 parts of 4.4'-diamino-2'-chlorosolution in the form of the sodium salt. It is a yellow solid stilbene-2-sulphonic acid, 30.5 parts of 4.4-diamino-2'- mass. After drying, the new stilbene derivative is a fiuorostilbene-2-sulphonic acid or by 29 parts of 4.4'-diyellowish powder which dissolves well in water. Because aminostilbene-2-sulphonic acid. of its strong fluorescence on cellulose substrata, this product also is excellently suitable for the brightening of cellu- Example 9 lose fibres. It can be used in aqueous solution alone or 9 CGHBNHGONH GH=CH NHCONHCH 1n the presence of washing and cleansing agents. 00

Products with a very similar action are obtained if in OCH; SIOSH the above example the parts of N-methyl-monoethanolamine are replaced by 42 parts of diethanolarnine or a P f 4'4"dlammo'2"meth9xystllbante-261111311011- f th 24 4 parts f monoethanolami lC 1c acid are dissolved at 20-30 with 0.53 part of calc.

Compared with derivatives of 4.4'-diaminostilbene-2.2- S dium carbonate in 300 parts of water and a solution of disulphonic acid having an analogous structure, these new 3 Parts of p y isocyaflate in 30 Parts of acetone i3 products have a more beautiful white shading as well as added While Stirring W611 Over a Period 0f 30 minutesbetter drawing power and an improved fastness to wash- A ter Stirring for 10 hours at 20-30", the yellowish ing. suspension is heated to 70 and parts of acetone are Example 7 0,11 N QCH=OHQ-NH N on:

HOCHzOHr-N OCaHs 01H 1 l1'CHzCHz0H H: CH:

If in Example 4, the 16.0 parts of 4.4-diamino-2- methoxy-stilbene-2-sulphonic acid are replaced by 16.7

added. Undissolved particles are filtered off from the hot solution, the reaction product is precipitated with parts of 4.4-diamino-2'-ethoxystilbene-2-sulphonic acid, sodium chloride and, after cooling, filtered ofi under then the trisodium salt of 4.4'-bis-[4-(m-sulphophenylsuction. It is washed with 2% sodium chloride solution. amino)-6-(B-hydroxyethyl-rnethylamino)-1.3.5 triazinyl- The 4.4 bis phenylureido 2' methoxy 2 sulpho (2) -amino] -2'-ethoxystilbene-2-sulphonic acid is obtained. stilbene formed is a pale beige coloured powder which dis- The product has very similar properties to that obsolves in hot water. This urea derivative produces very tained according to Example 4. In this case too, the N- strong blue to glue-greenish brightening efiects on cellumethyl-monoethanolarnine can be replaced by other prilose fibres. This product also produces a great increase mary or secondary aliphatic hydroxyalkylamines such as, of the degree of whiteness on wool, even on neutral apfor example, monoor di-ethanolamine without the propplication.

erties of the end product being greatly altered. A product with a very similar efiect is obtained if in Example 8 (H0 CHICHI):N N(0H,0H,0H),

30.4 parts of 4.4-diamino-2'-methylstilbene-Z-sulphonic acid, produced by reduction and saponification of 4.4'- the above example, the 3.2 parts of 4.4-diamino-2'- dinitro-2-methylstilbene-Z-sulphonic acid phenyl ester, are methoxystilbene-2-sulphonic acid are replaced by 3.34 dissolved with 5.3 parts of sodium carbonate in 1000 parts parts of 4.4'-diamino-2'-ethoxystilbene-Z-sulphonic acid.

(1113000 ONH-OH=CH A I Example I 7 N-CHzCHzOH N-CHzCHzOH \rrocmomli H0 om'enar i parts of sodium carbonate and then at 50-90 with excess N-methyl-monoethanolamine. The sodium salt of 4- :acetylamino 4 [2.4- di hydroxyethylmethyl 2 amino) 1.3.5 triazinylamino -.(.6.) 2 benzyloxy stilbene --'2' -sulphonic acid obtained is isolated -.by .salting out with sodium chloride. After drying, the product in the form of a yellow-grey powder, is soluble in hot Water and it produces useful brightening efiects both on cellulose :as --well as on wool-and Y silk.

=A product -with -similar activity .is obtained rif :in =this example the N-methyl-monoethanolamine is replaced by N-e'thyl-monoethanolamine.

The 4 amino --4 I stilbene 2 sulphonic acid used in this exampleds obtained fromthe 4 nitro 4' acetylamino 2 benzyl oxys'tilbene -2 sulphonic acid phenyl ester (M. P. 174) by partial-=saponification and reduction.

OCH:

4 acetylamino 2 methoxybenzaldehyde is condense'd with 4 nitrotoluene 2 -"sulphonic acid *phenol ester to form 4-acetylamino-2-methoxy-4-nitrostilbene- .2 -sulphonic.acid ,phenol .esteran'd thiszis -.saponifie'd to form '4--'amino--4'-- nitro2-methoxystilbene -2@sulphonic acid.

'SSIO parts of this acid are suspended in 400 parts of pyridine and 21 parts of.,p-nrethoxybenzoyl chloride are gradually added at.20-30'. The wholeis then stirred at -50..6.0 .until-no free amino groupscan be traced, which happensin a few minutes. The orange-brown solution is diluted with 1000 parts of 5% sodium chloridesolution, caustic soda lye is added until phenolphthalein paper turns red and the pyridine is distilled off with steam. The sodium salt which is filtered off after cooling, is dissolved in 1000 parts of hot water and reduced according to Bchamp with 30 parts of cast iron filings and 5 parts of acetic acid. The 4 amino 4 (4" methoxy benzoylamino) 2 methoxystilbene 2' sulphonic acid in the form of the sodium salt, which has been isolated in the usual way, is dissolved in 2500 parts of water and then reacted first at 0 with 18.5 parts of cyanuric chloride and 5.3 parts of sodium carbonate and then at 5090 with 42 parts of diethanolamine. The resulting sodium salt of 4 (4" methoxybenzoylamine) 2 methoxy 4' [2.4 di 13 hydroxyethylamino 1.3.5 triazinylamino (6)] stilbene 2' sulphonic acid is isolated by salting out with sodium chloride. The new product, a yellowish powder, dissolves in hot water and causes a strong brightening on cellulose fibres in daylight. 7

acetaniino 2 ben zoyloxy 3 -A less greenish product is obtained if dn this example "32 parts of 4 amino 4 nitrostilbene 2' sulphonic acid are used instead of the 4 amino 4 nitro -'2 methoxystilbene 2' sulphonic acid.

Example 12 NCHzCHzOH N% CH=CH NH- N Q Q SOzCHa SOaH NCHzCHgOH 36.8 parts of 4.4 diamino 2' methylsulphonyl stilbene 2 --"sulphonic-acid, produced by condensation of 4 -.znitro benzaldehyde 2 sulphonic acid with 4 nitro 2 methylsulphonyl 1 methylbenzene and reduction of the nitro groups to the amino groups, are dissolved in 1000 parts of water with 5.3 parts of sodium carbonate and reacted at 0, at a pH value of 5.5-6.5, with.3-6.9 parts of cyanuric chloride and 10.6 parts of sodium carb'onate. *50 parts of monoethandlamine 'are then added "to the thick yellowish suspension 'obtaineda11'dthe whole is stirred for 2'hours at 90-95 The sodium salt of 4.4 bis ---E'4: l -.di-( 3 hydroxyethylamino) 1.3.5 triazinyl- (2) amino] 2 methylsulphonyl stilbene 2 sul phonic acid formed is precipitated by salting out with sodium'chloride. After drying, the product forms a water soluble, pale yellowish powder, the aqueous solu- N (GiHiO H):

Example 13 White cotton poplin is treated for minutes at in a bath containing 0.005 g. of the sodium salt of 4.4- bis [4 (m sulphophenylamino) 6 (18 hydroxyethyl methylamino) 1.3.5 triazinyl (2) amino]- 2-methoxystilbene-2-sulphonic acid obtained according to Example 4 and 2 g. of Glaubers salt per litre (liquor ratio 1:30). After rinsing and drying, the material so treated has a much more white appearance in daylight than before treatment.

Example 14 11 -12 goods are then rinsed and dried. A dazzling white wash Y represents a member selected from the group conis obtained which has no unpleasant reddish tinge. sisting of H, halogen, lower alkyl, lower alkoxy, lower What I claim is: hydroxyalkoxy, lower alkylsulphonyl and sulphonic 1. As an optical brightening agent a stilbene coma id amide groups. pound which in the form of the free acid has the general 5 formula: 2. As an optical brightening agent a stilbene compound A1\ /A: N C-NH 011:0 NH-O N Y so H A: a A;

which in the form of the free acid has the formula: HO 02H4NH NHCzHAOH =N N= N N -NH CH=CHONH- N N HOCzH4N 00H; AOXH NHCzHAOH 3. As an optical brightening agent a stilbene compound which in the form of the free acid has the formula:

NH NH .N N= so=H N NH CH=CH NH N SOaH -N HO-CH2CH2-1TI O CHI SOzH III-CH2CH2OH CH; CH!

wherein: 30 A1, A2, A3 and A4 each represents a member selected 4. As an optical brightening agent a stilbene comtrom the group consisting of primary lower alkylpound which in the form'of the free acid has the formula: HOOHZCHFNH NHCHQOHIOH HoomomN Ht S0|H IFCHaGHsOH CH: CH; amino, primary lower hydroxyalkylamino, secondary 5. As an optical brightening agent a stilbene compound lower alkylarnino, secondary lower hydroxyalkylamino, which in the form of the free acid has the formula:

HomLcm-N N-CHgCH OH ("311: CH: primary mononuclear carbocyclic arylamino and mor- 50 6. As an optical brightening agent a stilbene compound pholine radicals, and which in the form of the free acid has the formula:

HOCHiCHiNH NHCHICHIOH No references cited. 

1. AS AN OPTICAL BRIGHTENING AGENT A STILBENE COMPOUND WHICH IS THE FORM OF THE FREE ACID HAS THE GENERAL FORMULA: 